One of the primary goals of an oil and gas operating company is to develop a reservoir asset in the most cost-efficient way. As such, it would be desirable for the operating company to identify and assess the risks that may impair the drainage of this hydrocarbon accumulation before production starts and as field development progresses. For example, it would be desirable for the operating company to identify the level of spatial connectivity within reservoir units, i.e., to identify flow barriers (baffles) caused either by the migration of salt, geological deposition of sediments, or by deposition of solid particles, heavy hydrocarbons, precipitated from reservoir fluids.
The presence of impermeable flow barriers may present a geological risk to hydrocarbon exploration. Flow barriers may isolate regions of a reservoir as separate fluid compartments, which are not in flow communication with other locations in the reservoir. Since each isolated fluid compartment may involve penetration by a wellbore to be drained, the number of compartments can impact the cost to develop a field.
Before a drilling operation commences a seismic survey may be performed whereby reflected seismology is used to explore, and thereby determine the properties of Earth's subsurface for the purpose of identifying features associated with hydrocarbon deposits. The seismic survey may be performed on land or water.
During or after a drilling operation, evaluations may be performed on the reservoir for various purposes, such as to manage the production of hydrocarbons from the reservoir. In one scenario, formation evaluation may involve drawing fluid from the reservoir into a downhole tool for testing or sampling. Various devices, such as probes or packers, may be extended from the downhole tool to isolate a region of the wellbore wall, and thereby establish fluid communication with the reservoir surrounding the wellbore. Fluid may then be drawn into the downhole tool using the probe or packer. Within the downhole tool, the fluid may be directed to one or more fluid analyzers, and sensors that may detect properties of the fluid. The properties of the fluid may be used to determine reservoir architecture, connectivity, compartmentalization, compositional gradients or the like.